1. Field of the Invention
The present invention relates to medicaments useful for preventive and/or therapeutic treatment of obesity, and to medicaments of improving lipid metabolism.
2. Related Art
Obesity is caused by insufficient exercise of habitual hyperphagia, or by metabolic disturbance due to genetic causes or endocrine diseases and other. Obesity may be a risk factor that causes various adult diseases such as myocardial infarct or arterial sclerosis, and it may also be a cause for deteriorating these diseases. Therefore, early therapeutic and preventive treatment of obesity is very important. Diet therapies or exercise therapies have been applied heretofore as the treatment of mild obesity, and drug therapies are sometimes used for serious obesity in combination with these therapies.
Hormone drugs, metabolic accelerators and other have been used heretofore for drug therapies of obesity and lipid metabolic disorder. For example, androgens such as dehydroepiandrosterone and 3-keto-xcex949-19-norsteroid are known to have anti-obesity action (Japanese Patent Unexamined Publication No. (Hei)2-275895/1990). These androgens are considered to activate intramuscular anabolism to induce the consumption of depot lipid. It is also known that 3-ketosteroids such as 4-cholesten-3-one (Japanese Patent Unexamined Publication No. (Hei)5-170651/1993) and 5-cholesten-3-one (Japanese Patent Unexamined Publication No. (Hei)7-165587/1995) have reducing activity on serum lipid and anti-obesity action. However, the aformentioned cholestenones, which have the enone structure derived from cholesterol, may possibly be absorbed and accumulated in the body, and therefore, they are not satisfactory medicaments from a viewpoint of safety.
The object of the present invention is to provide a medicament for the treatment of obesity and a medicament for improving lipid metabolism. More specifically, the object of the present invention is to provide a highly safe medicament for the treatment of obesity and a medicament for improving lipid metabolism which are not absorbed and accumulated in the body.
The inventors of the present invention conducted various studies to achieve the foregoing object, and as a result, they found that 24-alkylcholestenones and their analogues deriving from plant sterols (24-alkylcholesterols) have extremely potent decreasing effect on serum lipid and body fat, and are useful as an active ingredient of a medicament for the treatment of obesity and a medicament for improving lipid metabolism. They also found that these substances exhibit the desired physiological activities without being substantially absorbed in the body. The present invention was achieved on the basis of these findings.
The present invention thus provides a medicament includinding a compound selected from the group consisting of 24-alkylcholestan-3-ones and 24-alkylcholesten-3-ones as an active ingredient a compound. According to preferred embodiments of the present invention, there are provided the aforementioned medicament wherein the compound is selected from the group consisting of 24-alkylcholestan-3-ones, 24-alkylcholestmonoen-3-ones, 24-alkylcholestdien-3-ones, 24-alkylcholesttrien-3-ones and 24-alkylcholesttetraen-3-ones; the aforementioned medicament wherein the compound is represented by the following general formula (I): 
wherein R1 represents a lower alkyl group; R2 represents hydrogen atom, a halogen atom, hydroxy group, or oxo group; and said compound may have 1 to 4 double bonds at 1, 4, 5, 6, 7, 8, 8(14), 9(11), 11, 14, 15, 16, 22, 23, 24, 25 and/or 25(27)-position(s).
According to further preferred embodiments of the present invention, there is provided a medicament comprising 24-alkylcholest-5-en-3-one. Preferred examples of the 24-alkylcholest-5-en-3-one include 5-sitosten-3-one (24-ethylcholest-5-en-3-one), 5-campesten-3-one (24-methylcholest-5-en-3-one) and a mixture thereof, and the most preferred example includes 5-campesten-3-one.
These medicaments may be used for preventive and/or therapeutic treatment of obesity of mammals including humans, or for preventive and/or therapeutic treatment of diseases with abnormal lipid metabolism, for example, hyperlipidemia. The medicaments can also be used as an inhibitor of lipid absorption or an agent for decreasing serum lipid.
According to further aspects of the present invention, there are provided a method for preventive and/or therapeutic treatment of obesity, or a method for preventive and/or therapeutic treatment of diseases with abnormal lipid metabolism, which comprises the step of administering an effective amount of the aforementioned compound to a mammal including human; and a use of the aforementioned compounds for the manufacture of the aforementioned medicaments. According to still further aspects of the present invention, a health food and a health beverage containing the aforementioned compounds; a feed for livestock and a feed for a fish containing the aforementioned compounds; the aforementioned feed for livestock and the feed for a fish used for improving the quality of flesh; a pet food containing the aforementioned compounds; and use of the aforementioned compounds for the manufacture of the aforementioned food, feed, or pet food.